Beware of dogs, Paul says. Peter goes even further and refers to a dog as one who returns to vomit. Jesus noted that dogs should not be given the Holy.
To what are they referring? Obviously, this is all intended to be taken in a human context, not an animal one. So, what did the writers intend when they said "dog"?
First: a dog was an unclean animal. This means that it was not to be eaten, that it was unclean, to be avoided, and unholy. There are over 40 references to dogs in Scripture, but none are positive. In Psalms 22, they are likened to workers of iniquity, or the evil, God-hating demonic realm. They ingested and carried disease, and a close association would endanger your own health.
Second: dogs were known as scavengers. This tendency to eat carrion connected them to the notion of them being unclean. Wolves kill and desire to kill. Dogs did not kill to eat but scouted around, looking for smelly rotting meat on which to feast. This included the great dishonor of eating human flesh. Being eaten by dogs after death was about as bad an ending as a person of Israel could fathom.
Third: dogs are likened to strife in Prov. 26:17. Dogs love to fight. Fighting, bickering, yowling, and chewing on each other is a general pastime. They provoke conflict and revel in it. Is. 56 refers to them being greedy... one fight, or one dead body, is not enough; they always want more.
Fourth: dogs are noisy and complain. In Psalm 59, they make noise, belching, and complaining if they can't find enough to eat.
Fifth: they tend to vomit up the stuff they ate and then eat it again. Prov. 26:11, and 2 Peter 2:22. This speaks to both a return to evil after being cleansed and a desire to re-experience what was disgusting.
Sixth: Jesus used dogs as a